oh, maybe my bad english plays a role, but:
How many charges would have the demolition crew install on the perimeter?
How would they synchronize the charges with the impact?
How would they make sure that all of them go of (or majority of them) at the needed time?
Why would be the core column operation insufficient?
The core only scenario has the benefit of I column "armor" and a small amount of (dozen+/-?) charges
Anyway, the exterior collapse started exactly in place where the hanging floor 83 was connected to the exterior.

